In between molecules and self-assembled fibrillar networks: highly stable nanogel particles from a low molecular weight hydrogelator

Abstract

The preparation of molecular, non-polymeric nanogels from a low molecular weight hydrogelator is reported. The molecular nanogels are expected to overcome issues associated with the use of polymeric nanogels in biomedicine such as biodegradability, stimuli responsiveness, polydispersity, and batch-to-batch reproducibility. Nanogels formed by compound 1 were reproducibly prepared by sonication of a xerogel in PBS, with a total concentration of ca. 2 mM. The intensity averaged diameter of ca. 200 nm was determined by DLS. Electron microscopy (TEM and cryo-TEM) showed spherical particles. Light scattering (SALS) indicates that water is the main component of the nanoparticles, and the concentration of 1 in the nanogels is ca. 3 mg mL⁻¹. These particles can be considered to constitute an intermediate state between free molecules and self-assembled fibrillar networks. The nanogels present excellent temporal and thermal stability and accessible hydrophobic domains, as demonstrated by the incorporation of the fluorescent dye Nile Red.